Having or displaying a sense of overbearing self-worth or self-importance.

Example of an ignorant, and arrogant definition here on Urbandictionary.com

HollisterA store with high-quality clothes that are very hip and trendy. Usually look "pre-worn". It usually has cute instyle workers. It's a place you can get clothes to look great in. Usually emo or goth people make fun of hollister, abercrombie and fitch, or american eagle, Because they have nothing better to do with their pathetic lives and they can't afford it, and wouldn't look good in it anyway. Let's face it, If you were cute, YOU wouldn't boycott this store!

When a person is led to believe that they are in some way more superior to everybody else. Pride is fine up until a point, but as soon as you believe that you are in some special way better than everybody else, you become a dickhead.

Pretty much everybody on UrbanDictionary.com (including me) is arrogant.